Do not break existing core api

scm-core/src/main/java/sonia/scm/repository/util/AuthorUtil.java

@@ -32,6 +32,10 @@ import sonia.scm.user.User;
 
 public class AuthorUtil {
 
+  public static void setAuthorIfNotAvailable(CommandWithAuthor request) {
+    setAuthorIfNotAvailable(request, null);
+  }
+
   public static void setAuthorIfNotAvailable(CommandWithAuthor request, EMail eMail) {
     if (request.getAuthor() == null) {
       request.setAuthor(createAuthorFromSubject(eMail));
@@ -42,7 +46,7 @@ public class AuthorUtil {
     Subject subject = SecurityUtils.getSubject();
     User user = subject.getPrincipals().oneByType(User.class);
     String name = user.getDisplayName();
-    String mailAddress = eMail.createFallbackMailAddress(user);
+    String mailAddress = eMail != null ? eMail.createFallbackMailAddress(user) : user.getMail();
     return new Person(name, mailAddress);
   }
 

scm-core/src/test/java/sonia/scm/repository/util/AuthorUtilTest.java

@@ -0,0 +1,116 @@
+/*
+ * MIT License
+ *
+ * Copyright (c) 2020-present Cloudogu GmbH and Contributors
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+package sonia.scm.repository.util;
+
+import org.apache.shiro.subject.Subject;
+import org.apache.shiro.util.ThreadContext;
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.mockito.Answers;
+import org.mockito.Mock;
+import org.mockito.junit.jupiter.MockitoExtension;
+import sonia.scm.repository.Person;
+import sonia.scm.user.EMail;
+import sonia.scm.user.User;
+import sonia.scm.web.UserAgentParserTest;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.junit.jupiter.api.Assertions.*;
+import static org.mockito.Mockito.when;
+
+@ExtendWith(MockitoExtension.class)
+class AuthorUtilTest {
+
+  @Mock
+  private EMail eMail;
+
+  @Mock(answer = Answers.RETURNS_DEEP_STUBS)
+  private Subject subject;
+
+  @BeforeEach
+  void setUpSubject() {
+    ThreadContext.bind(subject);
+  }
+
+  @AfterEach
+  void tearDownSubject() {
+    ThreadContext.unbindSubject();
+  }
+
+  @Test
+  void shouldCreateMailAddressFromEmail() {
+    User trillian = new User("trillian");
+    when(subject.getPrincipals().oneByType(User.class)).thenReturn(trillian);
+    when(eMail.createFallbackMailAddress(trillian)).thenReturn("tricia@hitchhicker.com");
+
+    Command command = new Command(null);
+    AuthorUtil.setAuthorIfNotAvailable(command, eMail);
+
+    assertThat(command.getAuthor().getMail()).isEqualTo("tricia@hitchhicker.com");
+  }
+
+  @Test
+  void shouldUseUsersMailAddressWithoutEMail() {
+    User trillian = new User("trillian", "Trillian", "trillian.mcmillan@hitchhiker.com");
+    when(subject.getPrincipals().oneByType(User.class)).thenReturn(trillian);
+
+    Command command = new Command(null);
+    AuthorUtil.setAuthorIfNotAvailable(command);
+
+    assertThat(command.getAuthor().getMail()).isEqualTo("trillian.mcmillan@hitchhiker.com");
+  }
+
+  @Test
+  void shouldKeepExistingAuthor() {
+    Person person = new Person("Trillian McMillan", "trillian.mcmillian@hitchhiker.com");
+
+    Command command = new Command(person);
+    AuthorUtil.setAuthorIfNotAvailable(command);
+
+    assertThat(command.getAuthor()).isSameAs(person);
+  }
+
+  public static class Command implements AuthorUtil.CommandWithAuthor {
+
+    private Person person;
+
+    public Command(Person person) {
+      this.person = person;
+    }
+
+    @Override
+    public Person getAuthor() {
+      return person;
+    }
+
+    @Override
+    public void setAuthor(Person person) {
+      this.person = person;
+    }
+  }
+
+}